Double-ended cutter bit and socket construction



P 1964 c. B. KREKELER 3,148,002

DOUBLE-ENDED CUTTER BIT AND SOCKET CONSTRUCTION Filed May 5, 1959 lllllllllllllmllll INVENTOR. (4400: B. Ker/ 5; ER

United States Patent 3,148,652 DOUBLE-ENDED CUTTER BET AND SOCKET CONSTRUCTEON Claude B. Kreireler, Monfort Heights, Ohio, assignor to The Cincinnati Mine Machinery Co., Cincinnati, Ohio,

a corporation of Ohio Filed May 5, 1959, er. No. 811,626 7 Claims. (Cl. 2@-2.)

This invention relates to cutter bit and socket constructions for use on the rotating heads or traveling chainlink members of mining machinery, and in particular to that type of construction in which the cutter bits may be installed in the socket members by a simple driving operation and in which they may be removed therefrom by a simple prying operation. When the bits are engaged in the socket members, they are strongly held and also urged forwardly and downwardly by a suitable resilient means.

While a number of differing resilient holding means may be used, the invention will be described in connection with a particular structure which has hitherto been found excellent for the purpose. Reference may be made to several applications in the name of the present inventor: Serial No. 728,476, filed April 14, 1958, now Patent No. 2,965,365, and entitled Bits and Holding Means T herefor, which teaches among other things a preferred type of resilient holding means; Serial No. 811,167, filed May 5, 1959, now Patent No. 3,097,547, and entitled Means for the Removal and Installation of Cutter Bits in Mining Machinery, which teach s among other things a type of tool adapted for the operations necessary in the removal and replacement of the bits; and Serial No. 812,367, filed May 11, 1959, now Patent No. 3,088,721, and entitled Resilient Controlling Means, which teaches improved forms of replaceable resilient engagement means.

The bits hitherto used in combinations such as those referred to above have comprised a head and a shank, the head being provided with a hard cutting point in the forward direction, with an abutment means which, engaging the top surface of the socket member, limits the entry of the shank therein and thus establishes gauge, and with another (and usually undercut) abutment which may be engaged by a prying tool when it is desired to remove the bit. The bit shank has been configured on its rearward edge to coact with the resilient retaining means.

The bits are normally made of forged steel, and when properly tipped with a hard cutting alloy, are usually capable of being sharpened a few times, after which, however, they are thrown away or discarded as scrap. The use of an assembly in which the bits may be installed by driving and removed by prying has greatly diminished the cost of bit interchange, since it is now possible for one man to remove and install more bits in a unit length of time than could be handled by two men under prior conditions when the socket members were provided with set screws. Moreover, the entire operation may be carried on with safety under poor conditions of light or even in total darkness.

Those skilled in the art will understand, however, that bits must be interchanged at short intervals, frequently several times during the course of a sin le working shift. Thus the cost of the bits themselves is of sufilcient magnitude to be of considerable importance in the cost of mining.

It is the primary object of this invention to provide bits so constructed that their useful life is substantially prolonged, and in fact doubled, without a proportionate increase in original cost, and to provide a cutter bit and socket combination in which this may be accomplished.

It is an obg'ect of the invention to provide double-ended bits which nevertheless have all of the advantages in use, hitherto outlined for conventional single-ended bits.

These and other objects of the invention which will be set forth hereinafter or will be apparent to those skilled in the art upon reading these specifications, are accomplished by that construction and arrangement of parts of which certain exemplary embodiments will now be described. Reference is made to the accompanying drawings wherein:

FIGURE 1 is a side elevational view of one of the bits of this invention.

FIGURE 2 is a side elevational View of a modified form of cutter bit.

FIGURE 3 is an end elevation of the bit of FIGURE 2.

FIGURE 4 is a partial sectional view of the bit of FIGURE 1 engaged in a socket member.

The bits of this invention may be made, and preferably are made by forging. Other modes of manufacture are, however, not precluded, such as machining; and it is possible to make blanks for the bits of this invention by a die-stamping operation practiced upon plate metal of appropriate thickness. The precise thickness, as well as the other dimensions of the bits, does not constitute a limitation on the invention, but may be chosen by those skilled in the art in accordance with the requirements of strength for the particular cutting duty to be performed, keeping in mind the length of that portion of the bit which is to protrude from the socket member. The bits are preferably made symmetrical about a transverse central axis so that in use they may simply be turned end-for-end, although if desired a bit such as that shown in FIGURES 2 and 3 may be made with the cutting points extending in the same direction, and the prying abutments and the operating surfaces for the resilient holding means located respectively on the same sides of the bit, in which event it will be necessary to turn the bit through an angle of in both a horizontal and a vertical plane in order to change from the use of the cutting point on one end to the use of the cutting point on the other.

Referring first to FIGURE 1, a bit of elongated configuration is shown having a cutting point on each end. These cutting points are preferably located on or near the longitudinal axis of the bit, and preferably comprise inset pieces 2 and 3 of tungsten carbide, Carboloy, or other hard cutting alloy, placed in recesses cut in the bit and fastened in place by brazing, Welding or in other suitable ways. The present invention is not, however, limited to bits having separate cutting points. Bits can be made very cheaply from hardenable steel in a stamping operation where the cutting point is merely an integral part of the body of the bit.

The bits are tapered at each end. Behind the cutting point 2 there is a slanting surface 4 disposed at such an angle as to give cutting clearance (considering the disposition of the longitudinal axis of the bit when held in cutting position) and also at such an angle as to provide an adequate mass of metal behind the cutting point to back it against the cutting strains. At the front of the cutting point there is another slanting surface 5, disposed at a substantially smaller angle to the longitudinal axis of the bit, the junction of which will later be described. Similar slanting surfaces 6 and 7 are to be found at the other end of the bit.

The lateral edges of the bit are preferably formed as surfaces 8, and 1t 11 which are parallel to the longitudinal axis. The distance between the surfaces 8 and 9 and between the surfaces 10 and 11 are roughly equivalent to the distance between the front and rear edges of the perforation in a socket member in which the bit is to be used, as will later be made clear, the dimension of the bit from edge to edge being such as to provide the necessary cutting strength.

The surfaces 8 and 11, however, are offset from each other providing a gauge-determining abutment shoulder 12 located approximately at the transverse center axis of the bit. Similarly the surfaces 9 and 10 are offset from each other providing a gauge-determining abutment shoulder 13 facing in the opposite direction. Some variation in the position of these shoulders may be made depending upon the length of the bit desired to be embraced in the perforation of the socket member.

The surface 8 is interrupted by a notch-like configuration providing a slightly under-cut abutment 14 which may be engaged by a tool for prying the bit out of the socket member. A similar abutment 15 is formed at the opposite end of the bit.

The surface 9 is interrupted by a notch-like configuration which provides an operating surface 16 for coaction with the resilient retaining means hereinafter described. A similar configuration providing an operating surface 17 is formed in or adjacent the surface 11. The several notches described can be formed in the bit by forging, stamping, cutting or grinding, or by a combination of these expedients.

A modified form of cutter bit is shown in FIGURES 2 and 3. Like parts have been given like index numerals and do not require redescription. The essential difference between this bit and the one described above lies in the fact that gauge determining shoulders are not formed on the edges of the bit, the edges being parallel surfaces 13 and 19. Instead, gauge is determined by one or more abutment members 2G, 21 preferably formed integral with and protruding from the side edges of the bit. These abutment members rest on the top surface of a socket member as will be readily understood.

FIGURE 4 illustrates the bit of FIGURE 1 in use. A socket member 22, having an appropriate perforation 23, forms part of a mining machine chain or head. The lower end of the bit is received in the perforation as shown. A hole 24 is formed in the socket member from side to side intersecting the perforation. A resilient holding element is placed in this hole. It comprises a steel rod 25 encased in a mass of resilient rubbery substance 26. The rod is about as long as the side-to-side dimension of the socket member; and the rod 25 is preferably wholly encased in the rubbery body as to its end portions. The hole 24 is so located that the rod will lie partially at least within the perforation 23; and the rubbery substance is cut away to expose that portion of the rod which extends into the perforation 23. Consequently the rod coacts with the operating surface 17 of the bit exerting a strong downward and forward force on the bit. The rod must be displaced in the rubbery body when the bit is inserted by driving. The slanting bit surface '7 effects this displacement. The operating surface 17 is so placed that the rod 25 is still displaced when in contact with it. The shoulder 12 limits the extent to which the bit enters the socket perforation. The bit may be withdrawn by the engagement of a prying tool with the abutment 14.

It will be evident from FIGURE 4 that the bit may be withdrawn and reversed so as to permit the use of the cutting point 3. While gauge-determining abutment means have been shown and described as part of the bit, and while they are so provided, it is possible to use other gauge determining means. Thus the perforation in the socket member may be so configured as to limit the extent of entry of the bit by contacting surfaces 6 or 7 or both.

The cost of bits of this invention is only slightly more than the cost of conventional single-ended bits; but they may be expected to give twice the service life.

Modifications may be made in the invention without departing from the spirit of it. The invention having been described in certain exemplary embodiments, what is claimed as new and desired to be secured by Letters Patent is:

1. A double-ended cutting bit having an elongated metallic body tapered at both ends, there being cutting configurations located at each end, the body of said cutting bit having a cross-sectional shape both above and below the bit mid-section such as to enter a perforation in a socket member, means at about mid-section of said cutter bit to limit its entry into said perforation, and means on the portions of said bit above and below said mid-section to present an operating surface within said perforation for engagement with a resilient retaining means acting to urge the portion of said bit engaged within said perforation downwardly and forwardly as determined by the disposition of the cutting configuration on the portion of said bit not engaged within said perforation, edge portions of said cutter bit body being formed in two substantially parallel sections offset from each other so as to leave at about the mid-section of said cutter bit oppositely directed shoulders, one of said shoulders being adapted to engage the top surface of a socket member and constituting means limiting the entry of said bit into the perforation of said socket member.

2. The structure claimed in claim 1 including an abutrnent member formed near each end of said bit by means of a notch, said abutment members being engageable by a prying tool for the purpose of removing said bit from said socket member.

3. In a double-ended bit, an elongated metallic body having a cross-sectional shape substantially throughout its length such as to permit either end portion of the bit to be received in the perforation of a socket member, said bit having at each end a hard cutting element, said hard cutting elements being directed to opposite sides of the longitudinal axis of said metallic body, said metallic body having behind each hard cutting element an edge surface directed at a relatively high angle to said axis so as to insure the provision of cutting clearance and a sufiicient mass of metal behind said hard cutting element to furnish adequate backing, said bit having on the front side of each such cutting element an edge surface lying at a smaller angle to the said axis and so disposed as to defiect a resiliently mounted retaining element in the perforation of a socket member, and an operating surface adjacent said last surface adapted to be engaged by said resilient retaining element when an end of said bit is driven into the said perforation.

4. In a double-ended bit, an elongated metallic body having a cross-sectional shape substantially throughout its length such as to permit either end portion of the bit to be received in the perforation of a socket member, said bit having at each end a hard cutting element, said hard cutting elements being directed to opposite sides of the longitudinal axis of said metallic body, said metallic body having behind each hard cutting element an edge surface directed at a relatively high angle to said axis so as to insure the provision of cutting clearance and a sufficient mass of metal behind said hard cutting element to furnish adequate backing, said bit having on the front side of each such cutting element an edge surface lying at a smalier angle to the said axis and so disposed as to deflect a resiliently mounted retaining element in the perforation of a socket member, and an operating surface adjacent said last mentioned surface adapted to be engaged by said resilient retaining element when an end of said bit is driven into the said perforation, the said deflecting surfaces and operating surfaces being located at opposite sides of said bit body.

5. The structure claimed in claim 4 including abutment means formed at either end of said bit by means of a notch therein on a side opposite the deflecting and operating surfaces at that end, the said abutment being engageable by a prying tool for the removal of said bit from said socket member.

6. The structure claimed in claim 5 including means at about the mid-section of said bit for limiting the movement of either end thereof into the perforation of said socket member.

7. The bit claimed in claim 6 in combination with a socket member having a perforation therein to receive opposite ends of said bit, there being a hole in said socket member transverse to said perforation and intersecting it, and a resilient holding element in said hole comprising a metallic rod encased in a resilient rubbery substance, said resilient holding means being so located as to cause said rod to extend partially at least within said perforation, the rubbery resilient substance being cut away so as to expose said rod within said perforation, said rod being adapted to engage operating surfaces located toward either end of said bit from said mid-section and to exert on the portion of said bit Within said perforation a forward and downward force.

References Cited in the file of this patent UNITED STATES PATENTS 2,107,942 Holmes Feb. 8, 1938 2,574,735 Gentner Nov. 13, 1951 2,762,617 Joy Sept. 11, 1956 2,907,559 Brown et a1. Oct. 6, 1959 

3. IN A DOUBLE-ENDED BIT, AN ELONGATED METALLIC BODY HAVING A CROSS-SECTIONAL SHAPE SUBSTANTIALLY THROUGHOUT ITS LENGTH SUCH AS TO PERMIT EITHER END PORTION OF THE BIT TO BE RECEIVED IN THE PERFORATION OF A SOCKET MEMBER, SAID BIT HAVING AT EACH END A HARD CUTTING ELEMENT, SAID HARD CUTTING ELEMENTS BEING DIRECTED TO OPPOSITE SIDES OF THE LONGITUDINAL AXIS OF SAID METALLIC BODY, SAID METALLIC BODY HAVING BEHIND EACH HARD CUTTING ELEMENT AN EDGE SURFACE DIRECTED AT A RELATIVELY HIGH ANGLE TO SAID AXIS SO AS TO INSURE THE PROVISION OF CUTTING CLEARANCE AND A SUFFICIENT MASS OF METAL BEHIND SAID HARD CUTTING ELEMENT TO FURNISH ADEQUATE BACKING, SAID BIT HAVING ON THE FRONT SIDE OF EACH SUCH CUTTING ELEMENT AN EDGE SURFACE LYING AT A 